Inhibitory Effects of Cytosolic Ca²⁺ Concentration by Ginsenoside Ro Are Dependent on Phosphorylation of IP₃RI and Dephosphorylation of ERK in Human Platelets

Figure 6

Effects of G-Ro on inositol 1, 4, 5-trisphosphate receptor type I (IP₃RI) (Ser¹⁷⁵⁶) phosphorylation. (a) Effects of G-Ro on IP₃RI (Ser¹⁷⁵⁶) phosphorylation. Lane 1, unstimulated platelets (base); Lane 2, thrombin (0.05 U/mL); Lane 3, thrombin (0.05 U/mL) + G-Ro (50 μM); Lane 4, thrombin (0.05 U/mL) + G-Ro (100 μM); Lane 5, thrombin (0.05 U/mL) + G-Ro (200 μM); Lane 6, thrombin (0.05 U/mL) + G-Ro (300 μM). (b) Effects of G-Ro on IP₃RI (Ser¹⁷⁵⁶) phosphorylation in the presence of A-kinase inhibitor (Rp-8-Br-cAMPS) and G-kinase inhibitor (Rp-8-Br-cGMPS). Lane 1, thrombin (0.05 U/mL) + G-Ro (300 μM); Lane 2, thrombin (0.05 U/mL) + G-Ro (300 μM) + Rp-8-Br-cAMPS (250 μM); Lane 3, thrombin (0.05 U/mL) + G-Ro (300 μM) + Rp-8-Br-cGMPS (250 μM). Western blotting was performed as described in “Section 2.” The data are expressed as the mean ± standard deviation (). versus the thrombin-stimulated human platelets; versus the thrombin-stimulated human platelets in the presence of G-Ro (300 μM).

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